3 // The compiled code heap is structured into blocks.
5 // header format (bits indexed with least significant as zero):
7 // bits 1-2: type (as a code_block_type)
9 // bits 3-23: code size / 8
10 // bits 24-31: stack frame size / 16
12 // bits 3-end: code size / 8
14 cell owner; // tagged pointer to word, quotation or f
15 cell parameters; // tagged pointer to array or f
16 cell relocation; // tagged pointer to byte-array or f
18 bool free_p() const { return (header & 1) == 1; }
20 code_block_type type() const {
21 return (code_block_type)((header >> 1) & 0x3);
24 void set_type(code_block_type type) {
25 header = ((header & ~0x7) | (type << 1));
28 bool pic_p() const { return type() == CODE_BLOCK_PIC; }
35 size = header & 0xFFFFF8;
36 FACTOR_ASSERT(size > 0);
40 cell stack_frame_size() const {
43 return (header >> 20) & 0xFF0;
46 cell stack_frame_size_for_address(cell addr) const {
47 cell natural_frame_size = stack_frame_size();
48 // The first instruction in a code block is the prolog safepoint,
49 // and a leaf procedure code block will record a frame size of zero.
50 // If we're seeing a stack frame in either of these cases, it's a
51 // fake "leaf frame" set up by the signal handler.
52 if (natural_frame_size == 0 || addr == entry_point())
53 return LEAF_FRAME_SIZE;
54 return natural_frame_size;
57 void set_stack_frame_size(cell frame_size) {
58 FACTOR_ASSERT(size() < 0xFFFFFF);
59 FACTOR_ASSERT(!free_p());
60 FACTOR_ASSERT(frame_size % 16 == 0);
61 FACTOR_ASSERT(frame_size <= 0xFF0);
62 header = (header & 0xFFFFFF) | (frame_size << 20);
65 template <typename Fixup> cell size(Fixup fixup) const { return size(); }
67 cell entry_point() const { return (cell)(this + 1); }
69 // GC info is stored at the end of the block
70 gc_info* block_gc_info() const {
71 return (gc_info*)((uint8_t*)this + size() - sizeof(gc_info));
74 void flush_icache() { factor::flush_icache((cell)this, size()); }
76 template <typename Iterator> void each_instruction_operand(Iterator& iter) {
77 if (!to_boolean(relocation))
80 byte_array* rels = untag<byte_array>(relocation);
83 cell length = untag_fixnum(rels->capacity) / sizeof(relocation_entry);
85 for (cell i = 0; i < length; i++) {
86 relocation_entry rel = rels->data<relocation_entry>()[i];
87 iter(instruction_operand(rel, this, index));
88 index += rel.number_of_parameters();
92 cell offset(cell addr) const { return addr - entry_point(); }
94 cell address_for_offset(cell offset) const {
95 return entry_point() + offset;
98 cell scan(factor_vm* vm, cell addr) const;
99 cell owner_quot() const;
102 VM_C_API void undefined_symbol(void);
104 inline code_block* word::code() const {
105 FACTOR_ASSERT(entry_point != 0);
106 return (code_block*)entry_point - 1;
109 inline code_block* quotation::code() const {
110 FACTOR_ASSERT(entry_point != 0);
111 return (code_block*)entry_point - 1;